Unreal Engine 5.8 Preview

Depends on what you mean by “working well”… It still requires you to set SDL_VIDEO_DRIVER=x11 and tooltips still spawn a second instance in the task bar. But the UI is usable now without window rules.

Long standing broken stuff like Lightmass is still broken.

I was running into this as well until setting the SDL_VIDEO_DRIVER=x11 variable

If you’re in KDE you can add it in the app launcher editor:

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You can enable Lumen Medium Quality with sg.GlobalIlluminationQuality 1 + sg.ReflectionQuality 1 (in game) or set GI quality and Reflection Quality to Medium in the editor UI.

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I submitted a bug, but please don’t forget about the Transform/Rotate combined gizmo (named a widget in preferences). It is still in 5.8 preview, but it no longer functions. It is still very useful as the disc to transform x/y together is easy to get at any angle. The new gizmo is better than previous, but it still suffers from the issue of not being able to transform the x/y easily at certain angles. Plus the transform/rotate gizmo can rotate Z without switching to rotate gizmo. I however don’t use that feature much, I just love the disc for x/y.

And yet he still has an endearing quality, in a very Silent Hill type of way.

Hug the baby!

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@Dan_Hutnik I have updated a project using Mutable from 5.7.4 to the 5.8 preview. It was working but today the project does not open anymore. I have deleted Save/Intermediate/DerivedDataCache/Binaries folders but it didn’t help. It still shows this error message when I try to open the project:

appError called: Assertion failed: !Obj->HasAnyFlags(RF_NeedLoad|RF_NeedPostLoad|RF_ClassDefaultObject) || bIsOwnedByCDOOrArchetype [File:C:\UE5\UnrealEngine-5.8.0-preview-1\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [Line: 3605] 
Attempting to replace an object that hasn't been fully loaded: GroomCompiledData /Game//Mutable/CO_Base.CO_Base:CustomizableObjectGraph_0.CustomizableObjectNodeGroomConstant_0.UGroomData_722B71AF444304CBB3C16A9789486265 (Outer=CustomizableObjectNodeGroomConstant /Game/Mutable/CO_Base.CO_Base:CustomizableObjectGraph_0.CustomizableObjectNodeGroomConstant_0, Flags=0x00283000)

EDIT: resolved for now by copying the uasset mentioned over from the old 5.7 project. Project opens up again. I’ll monitor and report back if it becomes corrupted again.

Order Independent Transparency (OIT) fully broken!
Enabling it gives Ensure, render full of artifacts.
In 5.6-5.7 it give ensure, but at least works. Now - fully broken.

STR:

[/Script/Engine.RendererSettings]
r.OIT.SortedPixels=True

How do we use the Game Animation Sample Project with 5.8. the mover is rad but it wont create a new 5.8 project with that…

Screenshot 2026-05-17 020642

I started getting this warning after updating from 5.7.4 to 5.8.0.
I asked about this from the UE AI Assistant, and it gave me this response:

This is happening because of the “15.999 EiB” bug in your build of UE 5.8.0. Because the engine is calculating your total budget as a negative number or an underflowed integer (represented as 15.999 Exbibytes), the math (Used Memory / Budget) will always result in a value that exceeds your threshold, whether you set it to 85% or 100%.

Please let me know if this is really a bug. and also if it’s just a pop-up warning or does it actually affect my scene in any way?

I found another bug, when I migrate assets from the project. The migrated assets disappear as soon as the migration process completes—these only reappear when I restart the project.

doesn’t work on macOS (MBPro M5 pro) - just crashes on start

Will you add AI plugin like in unity for unreal engine 5?

Yikes, hopefully we’ll see medium Lumen getting improvements

i found an issue of monocular footage when import a video in to live link, unreal 5.7.4 wroking normal

That bug (or is that intended) I have in previous engine versions as well.

I really hoped that some of their Forward Looking UMG improvements will actually come into the engine one day.

Will CPU Lightmass receiving any updates? I know according to epics standpoint it is in maintenance mode (https://forums.unrealengine.com/t/recommended-lightmass-version/2709756/3)

I have the following issues with it (all using the stationary skylight):

  • reflections on materials with clearcoat shading (legacy and Substrate) are incorrectly handled in areas that are shadowed by the skylight.

  • GI is not working.

  • shading subsurface/ two sided foliage are not working, rendering the backside completely black without any skylight contribution.

Here an example of missing GI (tunnel lights) and the reflections on the car

…and here an example with the missing lit backside of foliage.

here a full video where the car drives into the tunnel, any foliage you see has the two sided foliage type enabled.

I experience some strange issues with Chaos Cloth with UE 5.8.

When I try to create a Wardrobe Item what I do is:

  1. Create Cloth Asset using USDImport (same issue happens with StaticMesh Import though)
  2. Create Outfit Asset - link Cloth Asset here
  3. Create Wardobe Item - Link Outfit Asset here.

For some reason I CAN see a preview of the mesh in Cloth Asset (construction viewport) as shown below:

But I CAN NOT see it in Simulation Viewport.

Same applies for Outfit Asset: The mesh is not visible in Costruction nor Simulation Viewport.

The thumbnail preview is created but actual asset is not visible.

Same applies for Wardobe Item when added to Metahuman Creator.

So, am I missing something in regards to that proccess?

The default WI_DefaultOutfit that is coming with MHC appears to be working properly.

Yeah my entire project sounds like bit crushed to hell and sounds like hell too. Even external apps are getting affected. Changing the audio API to XAudio2 resolved it for me

@Dan_Hutnik

Summary: Chooser / PoseSearch seems to be broken in 5.8 Preview 1; sometimes returns invalid values in 5.8p1, but always works in 5.7.x.

Reproduction: create GASP sample project for 5.7, open in 5.8p1, connect missing Sim Context pins and select CMC or Mover pawn to play (happens with both).

Go climb obstacles and the pawn will start floating at some point.

The Chooser returns an invalid/empty montage to play for the pawn. This never happens in 5.7.x

Video of this issue:

Since Megalights is now production ready, how does it perform in VR?